Typical control apparatuses of the type mentioned above, called demand controllers, for example, are disclosed in Japanese Patent Unexamined Publication (KOKAI) Nos. 5-164376/93, 7-55225/95, and 5-95629/93. The control apparatuses disclosed in these publications are all constructed such that a signal requesting a demand (reduction of power) is supplied to an air conditioner from the control apparatus through a wire or line.
In case a signal requesting a demand is supplied to an air conditioner through a line, the work for wiring a signal line is accompanied. In consideration of an outward appearance of the wiring, it is customary that such a signal line is wired while the work for constructing a new house is undergoing, and it is rare that a demand control apparatus is installed after the completion of construction of a new house and installation of the demand control apparatus after the new house is completed is prohibited.
In view of the above problem, the present invention provides a control apparatus like a demand controller which can be installed after a completion of construction of a new house, in which a radio wave communication hardly attenuated in the wall and an infrared signal capable of easily communicating with an air conditioner without a need of a provision of any additional device are used in combination.